Workflow engine BPMN, Drools, etc or ESB?

We currently have an application that is based on an in-house developed workflow engine with YAML based DSL. We are looking to move parts of it to Java.

I have discovered a number of java solutions like Intalio, JBPM, Drools Expert, Drools Flow etc. They appear to be aimed at businesses where the business analyst creates the workflows using a grap开发者_StackOverflowhical editor and submits them to the workflow engine. They seem geared towards ease of use for non-technical people rather than for developers with a focus on human interaction.

The workflows tend to look like.

Discover-a-file        -\
                         -> join -> process-file -> move-file -> register-file 
Discover-some-metadata -/

If any step fails we need to retry it X times. We also need to be able to stop the system and be able to restart it and have it continue from where it was (durable).

Some of our workflows can be defined by a set of goals we need to achieve so Jess's backwards rule chaining sounds interesting but it is not open source.

It might be that what we are after is a Finite State Machine engine or just an Enterprise Service Bus and do everything as JMS queues.

Is there a good open source workflow engine that is both standards-based but also geared towards developers. We don't particular want to use a graphical workflow designer or write reams of XML and it should ideally be in Java or language agnostic (makes REST/Soap calls to external services).

Thanks, Tom

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Both Activiti and Bonita are open source and standard based (BPMN2). See for example this blog post.

Ruote is not standard based but seems close to your DSL approach and runs on a JVM thanks to JRuby.

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Intaloi an open source BPM engine it offers a BPMN-support Designer and a BPEL engine. it's written in Java.

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Camunda BPM is a developer-friendly Open Source workflow engine that is based on the open standards BPMN 2.0, DMN 1.1 and CMMN 1.1.

While it does come with a comfortable graphical workflow designer it also ships with a fluent API to build workflows programmatically. Camunda is written in Java, but can also be invoked from other languages via its REST API and it can make REST/Soap calls to external services.

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jBPM 5 (open source, ASL, BPMN2) is just released and it's the best of Drools Flow and jBPM 4. It's lightweight but it can also integrate deeply with the Drools rule engine to make decisions.

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For anyone looking for Python based enterprise grade solution.

Zengine, is GPL3 BPMN workflow based framework with Tornado, Rabbit AMQP, advanced permissions, extensible scaffolding features and more.

Built on top of following major components;

• SpiffWorkflow: Powerful workflow engine with BPMN 2.0 support.
• Tornado: Tornado is a Python web framework and asynchronous networking library.
• Pyoko: Django esque ORM for Riak KV store. RabbitMQ: Fast, ultrasharp AMQP server written with legendary Erlang lang.